Complete ID & Passport Photo Size Guide (mm, Pixels & DPI)

Last updated: 2026-06-25

What is an ID photo

An ID photo is a standardized portrait used to verify identity. It is used widely on passports, ID cards, driver's licenses, student cards, resumes, certificates, and various official forms. Unlike a regular portrait, it must follow set rules for size (dimensions), background, face position and ratio, expression, and clothing; if it falls outside the rules, it can be rejected. That is why, before taking or editing a photo, the most important thing is to know exactly the size your issuer requires.

Sizes are usually written as "width x height" in millimeters (mm) or centimeters (cm). The same photo needs pixel (px) units for printing, so it helps to also know how to convert between mm/cm and pixels.

ID photo sizes by use case at a glance

The table below lists commonly used sizes by use case with print pixels at 300 DPI. The pixel values assume a print resolution of 300 DPI; using a different DPI changes the values.

In practice, "ID photo" usually means the everyday 30 x 40 mm (3 x 4 cm) size. When a print shop produces a sheet, several of these fit together, which is part of why this size is treated as a standard. A passport photo at 35 x 45 mm is slightly larger and has stricter rules. To see exact mm/pixels quickly, open the ID & passport photo size guide tool and pick a use and DPI.

Additional passport photo rules

A passport photo is not just about matching the 35 x 45 mm size. There are separate rules for the proportion and position of the face, the background, and the expression. Commonly cited rules include the following.

• Head height — the distance from crown to chin should be about 32-36 mm. A face that is too large or too small can be rejected.
• Background — a plain white background is the rule; patterns, shadows, and borders are not allowed.
• Expression and pose — face the camera with a neutral expression and closed mouth, and keep both ears and eyebrows unobstructed.
• Glasses and hats — avoid glasses with glare, tinted lenses, and hats or head coverings.

Passport photo rules can change, so before applying it is safest to check the latest photo requirements, e.g. the U.S. Department of State passport photo guidance. The values on this page are commonly used reference figures.

How to convert mm/cm to print pixels

For online submissions or direct printing, you need to convert the size to pixels. The key formula is just one.

Pixels = length (inches) × DPI, and 1 inch = 25.4 mm = 2.54 cm. So for mm it becomes pixels = mm / 25.4 × DPI, and for cm it becomes pixels = cm / 2.54 × DPI.

As the table shows, for the same 35 x 45 mm photo, a higher DPI means more pixels and a sharper print. 72-96 DPI is fine for screen use, but 300 DPI or higher is recommended for printing and submission. To calculate any size and DPI yourself, use the print pixel & DPI calculator. You can also use the same tool in reverse to find the printable size from the pixels of a photo you already have.

Background color and file format

ID photo backgrounds depend on the use. Official ID photos such as passports and national ID cards require a plain white background. Company, school, and certificate submissions sometimes allow a light gray or blue background. In every case, avoid patterns, strong shadows, and borders, and use a solid color to be safe.

For file format, JPG is standard for print and submission. JPG is small and widely compatible, so most submission systems accept it. Use PNG when you need a transparent background or are compositing. Online submissions often have a file size limit (for example, a few hundred KB), so after matching the size, check the file size too.

Resizing a photo to the required size

To match an existing photo to the required size, you resize it to the target pixels. If the source and target aspect ratios differ, you choose one of three modes. Crop (cover) keeps the ratio and trims the edges to fill the frame with no margin, fit (contain) keeps the whole image but fills the leftover area with the background color, and stretch ignores the ratio and forces the exact target size. ID photos usually need to keep face proportions, so use crop or fit.

With the photo resizer, you can upload a photo, pick a preset (passport, ID, etc.) or enter target pixels directly, and resize and download right away. All processing happens on the browser canvas, so your image is never sent to a server, and you can use it without privacy concerns.

Key takeaways

• An everyday ID photo is 30 x 40 mm and a passport photo is 35 x 45 mm as a standard.
• Print pixels = mm / 25.4 x DPI, and the recommended print resolution is 300 DPI or higher.
• Official ID photo backgrounds should be white, with no patterns, shadows, or borders.
• When ratios differ, choose the right mode among crop, fit, and stretch.
• Always verify the final size, background, and file size with the issuer and official authorities first.

Last updated: 2026-06-25